<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    
    <script>
        new Promise((resolve,reject) =>{
            setTimeout(() => {
                // resolve('hello')
                //失败调用error
                reject('error')
            }, 1000);
        }).then((data)=>{
            //
            console.log(data);
            console.log(data);
            console.log(data);
        }).catch((err)=>{
            console.log(err);
            
        })
    </script>
</body>
</html>